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+/* add.c: bcmath library file. */
+/*
+ Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
+ Copyright (C) 2000 Philip A. Nelson
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details. (COPYING.LIB)
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to:
+
+ The Free Software Foundation, Inc.
+ 59 Temple Place, Suite 330
+ Boston, MA 02111-1307 USA.
+
+ You may contact the author by:
+ e-mail: philnelson@acm.org
+ us-mail: Philip A. Nelson
+ Computer Science Department, 9062
+ Western Washington University
+ Bellingham, WA 98226-9062
+
+*************************************************************************/
+
+#include <config.h>
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <stdarg.h>
+#include "bcmath.h"
+#include "private.h"
+
+
+/* Here is the full add routine that takes care of negative numbers.
+ N1 is added to N2 and the result placed into RESULT. SCALE_MIN
+ is the minimum scale for the result. */
+
+void
+bc_add (n1, n2, result, scale_min)
+ bc_num n1, n2, *result;
+ int scale_min;
+{
+ bc_num sum = NULL;
+ int cmp_res;
+ int res_scale;
+
+ if (n1->n_sign == n2->n_sign)
+ {
+ sum = _bc_do_add (n1, n2, scale_min);
+ sum->n_sign = n1->n_sign;
+ }
+ else
+ {
+ /* subtraction must be done. */
+ cmp_res = _bc_do_compare (n1, n2, FALSE, FALSE); /* Compare magnitudes. */
+ switch (cmp_res)
+ {
+ case -1:
+ /* n1 is less than n2, subtract n1 from n2. */
+ sum = _bc_do_sub (n2, n1, scale_min);
+ sum->n_sign = n2->n_sign;
+ break;
+ case 0:
+ /* They are equal! return zero with the correct scale! */
+ res_scale = MAX (scale_min, MAX(n1->n_scale, n2->n_scale));
+ sum = bc_new_num (1, res_scale);
+ memset (sum->n_value, 0, res_scale+1);
+ break;
+ case 1:
+ /* n2 is less than n1, subtract n2 from n1. */
+ sum = _bc_do_sub (n1, n2, scale_min);
+ sum->n_sign = n1->n_sign;
+ }
+ }
+
+ /* Clean up and return. */
+ bc_free_num (result);
+ *result = sum;
+}
+